Upper Plenum

One major accident of interest in the High Temperature Gas-Cooled Reactors is the Pressurized Conduction Cooldown (PCC) scenario. The PCC scenario occurs after circulator failure which results in a loss of forced convection to the core, but the loop stays pressurized since there is no breach in the boundary. This results in a large buoyancy force that through natural convection reverses the flow of the core coolant loop to circulate into the upper plenum of the VHTR. Computer codes may be improved to simulate this phenomenon, but benchmark data is needed to validate the simulations.

An experimental facility was design and constructed to study the mixing of hot fluid coming from the core channels and reaching the reactor upper plenum. PIV and other visualization techniques are being applied to measure the velocity field in the upper plenum.

 

Experimental Facility Overview

Plenum -web

 

PIV Results

Plenum -1-webPlenum -2-web